The broad long term obectives of the proposed research are to determine the effect of coastal pollution on the species and quantity of both marine and pathogenic bacteria sequestered by selected algal biota on near shore coastal reefs and the role that seasonal and climatic conditions play in this process. The benthic dinoflagellate Ostreopsis lenticularis will be used as a model system to analyze changes in sequestered bacterial flora resulting from increased terrestrial development and human habitation the resulting pollution in these coastal marine environments. The proposed research will provide a means of evaluating magnitude and rate of the recruitment of pathogenic bacteria by benthic microflora on fringing coastal reefs and their potential role in the transmission of infectious diseases in the marine food chain. The hypothesis to be tested in this work is that benthic marine micro-algae will sequester among their bacterial symbionts pathogenic bacteria introduced into polluted coastal environments.